User blog comment:MegaGyarados/You Guys NEED, AND I MEAN NEED, to understand this (This isn’t about teams again)/@comment-32358261-20180215091539/@comment-32358261-20180215211237

In generation 1 it did due to an exploit in the code that had a small fail chance.

From generation 2 and onward it’s impossible since it’s catch rate multiplier is 255x that completely overrides the formula and guarantees a catch